ldnode

Solid server in NodeJS

Ldnode lets you run a Solid server on top of the file-system. You can use it as a command-line tool (easy) or as a library (advanced).

Solid Features supported

• [x] Linked Data Platform
• [x] Web Access Control
• [x] WebID+TLS Authentication
• [x] Real-time live updates (using WebSockets)
• [x] Identity provider for WebID
• [x] Proxy for cross-site data access
• [ ] Group members in ACL
• [ ] Email account recovery

Command Line Usage

Install

To install, first install Node and then run the following

$ npm install -g ldnode

Run a single-user server (beginner)

To run your server, simply run ldnode with the following flags:

$ ldnode --port 8443 --ssl-key path/to/ssl-key.pem --ssl-cert path/to/ssl-cert.pem
# Solid server (ldnode v0.2.24) running on https://localhost:8443/

First time user? If you have never run ldnode before, let's get you a WebID to access your server.

$ ldnode --port 8443 --ssl-key path/to/ssl-key.pem --ssl-cert path/to/ssl-cert.pem
# Action required: Create your admin account on https://localhost:8080/
# When done, stop your server (<ctrl>+c) and restart without "--create-admin"

If you want to run ldnode on a particular folder (different from the one you are in, e.g. path/to/folder):

$ ldnode --root path/to/folder --port 8443 --ssl-key path/to/ssl-key.pem --ssl-cert path/to/ssl-cert.pem
# Solid server (ldnode v0.2.24) running on https://localhost:8443/

How do I get the --ssl-key and the --ssl-cert?

You need an SSL certificate you get this from your domain provider or for free from Let's Encrypt!.

If you don't have one yet, or you just want to test ldnode, generate a certificate (DO NOT USE IN PRODUCTION):

$ openssl genrsa 2048 > ../localhost.key
$ openssl req -new -x509 -nodes -sha256 -days 3650 -key ../localhost.key -subj '/CN=*.localhost' > ../localhost.cert

Run multi-user server (intermediate)

You can run ldnode so that new users can sign up, in other words, get their WebIDs username.yourdomain.com.

Pre-requisites:

• Get a Wildcard Certificate
• Add a Wildcard DNS record in your DNS zone (e.g.*.yourdomain.com)
• (If you are running locally) Add the line 127.0.0.1 *.localhost to /etc/hosts

$ ldnode --allow-signup --port 8443 --cert /path/to/cert --key /path/to/key --root ./accounts

Your users will have a dedicated folder under ./accounts. Also, your root domain's website will be in ./accounts/yourdomain.tld. New users can create accounts on /accounts/new and create new certificates on /accounts/cert. An easy-to-use sign-up tool is found on /accounts.

Run the Linked Data Platform (intermediate)

If you don't want WebID Authentication and Web Access Control, you can run a simple Linked Data Platform.

# over HTTP
$ ldnode --port 8080 --no-webid
# over HTTPS
$ ldnode --port 8080 --ssl-key key.pem --ssl-cert cert.pem --no-webid

Note: if you want to run on HTTP, do not pass the --ssl-* flags, but keep --no-webid

Extra flags (expert)

The command line tool has the following options

Usage: ldnode [options]

Options:
   --version          Print current ldnode version
   -v, --verbose      Print the logs to console

   --root             Root folder to serve (defaut: './')
   --port             Port to use
   --webid            Enable WebID+TLS authentication (use `--no-webid` for HTTP instead of HTTPS)
   --ssl-key          Path to the SSL private key in PEM format
   --ssl-cert         Path to the SSL certificate key in PEM format
   --allow-signup     Allow users to register their WebID on subdomains

   --create-admin     Allow a user to set up their initial identity in single-user mode
   --no-live          Disable live support through WebSockets
   --default-app      URI to use as a default app for resources (default: https://linkeddata.github.io/warp/#/list/)
   --proxy            Use a proxy on example.tld/proxyPath
   --file-browser     URI to use as a default app for resources (default: https://linkeddata.github.io/warp/#/list/)
   --data-browser     Enable viewing RDF resources using a default data browser application (e.g. mashlib)
   --suffix-acl       Suffix for acl files (default: '.acl')
   --suffix-meta      Suffix for metadata files (default: '.meta')
   --session-secret   Secret used to sign the session ID cookie (e.g. "your secret phrase")
   --no-error-pages   Disable custom error pages (use Node.js default pages instead)
   --error-pages      Folder from which to look for custom error pages files (files must be named <error-code>.html -- eg. 500.html)
   --mount            Serve on a specific URL path (default: '/')
   --force-user       Force a WebID to always be logged in (useful when offline)
   --strict-origin    Enforce same origin policy in the ACL

Library Usage

Install Dependencies

npm install

Library Usage

The library provides two APIs:

• ldnode.createServer(settings): starts a ready to use Express app.
• lnode(settings): creates an Express that you can mount in your existing express app.

In case the settings is not passed, then it will start with the following default settings.

{
  cache: 0, // Set cache time (in seconds), 0 for no cache
  live: true, // Enable live support through WebSockets
  root: './', // Root location on the filesystem to serve resources
  secret: 'node-ldp', // Express Session secret key
  cert: false, // Path to the ssl cert
  key: false, // Path to the ssl key
  mount: '/', // Where to mount Linked Data Platform
  webid: false, // Enable WebID+TLS authentication
  suffixAcl: '.acl', // Suffix for acl files
  proxy: false, // Where to mount the proxy
  errorHandler: false, // function(err, req, res, next) to have a custom error handler
  errorPages: false // specify a path where the error pages are
}

Have a look at the following examples or in the examples/ folder for more complex ones

Simple Example

You can create an ldnode server ready to use using ldnode.createServer(opts)

var ldnode = require('ldnode')
var ldp = ldnode.createServer({
    key: '/path/to/sslKey.pem',
    cert: '/path/to/sslCert.pem',
    webid: true
})
ldp.listen(3000, function() {
  // Started Linked Data Platform
})

Advanced Example

You can integrate ldnode in your existing Express app, by mounting the ldnode app on a specific path using lnode(opts).

var ldnode = require('ldnode')
var app = require('express')()
app.use('/test', ldnode(yourSettings))
app.listen(3000, function() {
  // Started Express app with ldp on '/test'
})
...

Logging

Run your app with the DEBUG variable set:

$ DEBUG="ldnode:*" node app.js

Testing ldnode Locally

Pre-Requisites

In order to really get a feel for the Solid platform, and to test out ldnode, you will need the following:

1. A WebID profile and browser certificate from one of the Solid-compliant identity providers, such as databox.me.

2. A server-side SSL certificate for ldnode to use (see the section below on creating a self-signed certificate for testing).

While these steps are technically optional (since you could launch it in HTTP/LDP-only mode), you will not be able to use any actual Solid features without them.

Creating a certificate for local testing

When deploying ldnode in production, we recommend that you go the usual Certificate Authority route to generate your SSL certificate (as you would with any website that supports HTTPS). However, for testing it locally, you can easily generate a self-signed certificate for whatever domain you're working with.

For example, here is how to generate a self-signed certificate for localhost using the openssl library:

ldnode --webid --port 8443 --cert ../localhost.cert --key ../localhost.key -v

Note that this example creates the localhost.cert and localhost.key files in a directory one level higher from the current, so that you don't accidentally commit your certificates to ldnode while you're developing.

Accessing your server

If you started your ldnode server locally on port 8443 as in the example above, you would then be able to visit https://localhost:8443 in the browser (ignoring the Untrusted Connection browser warnings as usual), where your ldnode server would redirect you to the default viewer app (see the --file-browser server config parameter), which is usually the github.io/warp file browser.

Accessing most Solid apps (such as Warp) will prompt you to select your browser side certificate which contains a WebID from a Solid storage provider (see the pre-requisites discussion above).

Editing your local /etc/hosts

To test certificates and account creation on subdomains, ldnode's test suite uses the following localhost domains: nic.localhost, tim.localhost, and nicola.localhost. You will need to create host file entries for these, in order for the tests to pass.

Edit your /etc/hosts file, and append:

# Used for unit testing ldnode
127.0.0.1 nic.localhost, tim.localhost, nicola.localhost

Running the Unit Tests

$ npm test
# running the tests with logs
$ DEBUG="ldnode:*" npm test

In order to test a single component, you can run

npm run test-(acl|formats|params|patch)

Contributing

ldnode is only possible due to the excellent work of the following contributors:

Do you want to contribute?

• Join us in Gitter to help with development or to hang out with us :)
• Create a new issue to report bugs
• Fix an issue

Have a look at CONTRIBUTING.md.

License

MIT